DE102021109114B3 - Pulley decoupler - Google Patents

Abstract

Pulley decoupler (1) with an input side (2) and an output side (3) and a common axis of rotation (4) and at least one spring element (5) acting between the input side (2) and the output side (3), against the spring action of which the input side (2) and the output side (3) can be rotated relative to one another in a circumferential direction (6), the output side (3) being rotatably mounted relative to the input side (2) via a bearing (7) arranged on the input side (2), the output side ( 3) starting from the bearing (7) on a first side (8) of the at least one spring element (5) in a radial direction (9) outwards to a belt section (10), wherein starting from the belt section (10) and a cover (12) extends inwards along the radial direction (9) on a second side (11) opposite the first side (8) in an axial direction (13) extending along the axis of rotation (4).

Description

The invention relates to a belt pulley decoupler with an input side and an output side and a common axis of rotation as well as at least one spring element acting between the input side and the output side, by means of which the input side and the output side can be rotated relative to one another in the circumferential direction. In particular, a belt pulley decoupler comprises at least one damping device (torsional vibration damper—TSD) in addition to the at least one spring element.

The pulley decoupler is particularly useful for connecting a pulley to a crankshaft of a prime mover, e.g. B. a motor vehicle provided. This is to prevent the transmission of torsional vibrations, e.g. B. the prime mover on the belt driven by the pulley, at least reduced or prevented. However, the pulley decoupler can also form a two-mass flywheel.

From the DE 10 2017 111 664.8 and DE 10 2017 113 043.8 as well as the DE 10 2013 206 444 A1 such belt pulley decouplers or drive wheels are known, in which case the intermediate space (e.g. at least partially filled with a lubricant)/volume (spring receiving space there) is sealed off from an external environment via a sealing and positioning device on the one hand and the drive pulley in the axial direction on the other direction is positioned. For this purpose, a spring element (plate spring) is arranged between the traction mechanism connection area (output side) and the shaft connection area (input side) that braces the areas in an axial direction relative to one another. The spring element is held in place by friction rings (without an elastic sealing lip), which also ensure a sealing effect.

The requirements for sealing the gap are very high. Due to the higher requirements, a wide variety of contamination tests are carried out, e.g. B. Splash water tests, mud brine tests, dust tests, salt spray tests, wat tests.

There is a constant need for components for motor vehicles such. B. Pulley decoupler and to reduce manufacturing costs.

Proceeding from this, the present invention is based on the object of providing a belt pulley decoupler which is as simple as possible and in particular comprises as few components as possible.

This object is solved with a pulley decoupler according to the features of independent claim 1. Further advantageous developments of the invention are given in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically meaningful manner and can define further refinements of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, with further preferred configurations of the invention being presented.

A belt pulley decoupler is proposed, with an input side and an output side and a common axis of rotation and at least one spring element acting between the input side and the output side, against the spring action of which the input side and the output side can be twisted against one another in the circumferential direction. The output side is rotatably mounted relative to the input side via a (plain) bearing arranged on the input side. The output side extends from the (plain) bearing on a first side of the at least one spring element outwards in a radial direction to a belt section (on which a belt can be arranged, which can be driven via the belt section or via the pulley decoupler).

A cover extends from the belt portion and inwards along the radial direction on a second side opposite the first side in an axial direction extending along the axis of rotation. A friction ring consisting exclusively of plastic material is arranged between the cover and the input side, which friction ring has at least a first partial area which is elastically deformable and which generates a spring force acting in the axial direction.

In particular, the friction ring replaces the otherwise customary combination of friction ring and metal plate spring, so that the number of parts can be reduced and assembly can be simplified by the friction ring.

The friction ring can in particular compensate for an axial tolerance of the gap between the input side and the cover caused by possibly low tolerance requirements, at least with respect to the axial direction, possibly also with respect to the radial direction.

The spring force of the friction ring or the first partial area can in particular apply a contact pressure force acting in the axial direction that is sufficient to achieve the required sealing effect, so that leakage of lubricant through the gap bridged by the friction ring can be avoided.

In addition to providing the sealing effect, the friction ring can apply a contact pressure force acting in the axial direction, so that deliberate friction is provided, by means of which a resonance-induced build-up of torsional vibrations can be damped. The contact pressure applied by the friction ring can in particular be a multiple of the contact pressure required for the sealing effect, in particular at least 1.5 times, preferably at least 2 times, more preferably at least 3 times and particularly preferably at least 5 times.

Compared to a rather light contact of a conventional sealing device, which can be achieved, for example, by using a soft material of the sealing device, in particular natural or synthetic rubber, and a slight press fit, the material of the friction ring and in particular of the first partial area can be significantly harder than rubber. In order to provide a significant friction effect, for which a separate friction device would otherwise be required, mechanical bracing can be achieved with a significantly higher contact pressure. The number of components and the manufacturing costs can be reduced by saving on a separate friction device, which can be designed, for example, in the manner of a slipping clutch.

The function of a seal and the function of a friction device can be summarized and combined with the friction ring in one component, in which a high contact pressure can be generated with the aid of the first partial area. This leads to a robust design in which few components are provided and these components are designed to be stable and resistant to mechanical loads.

With the provision of the friction ring, a sealing membrane can be omitted and an increase in the coefficient of friction takes place through a reduced number of joints (due to the omission of the sealing membrane) in the screw connection.

In particular, the friction ring is designed in one piece. A material mix of an elastomeric sealing ring and a spring element made of spring steel is thereby avoided, so that the number of components and the manufacturing costs can be reduced. A plastic material that is harder than rubber but softer than steel can preferably be selected for the one-piece friction ring. Here, the knowledge is exploited that when using grease as a lubricant in the receiving space of the spring element, there are lower tightness requirements for the friction ring compared to a rather thin oil, which can also be achieved with a material that is harder than rubber or caoutchouc.

In addition, a rather high contact pressure force is applied by the friction ring, which can achieve an adequate sealing effect even with a harder material for the friction ring. If, in addition, if necessary, significant friction is to be deliberately provided, considerations based on a low friction effect are superfluous when selecting the material for the friction ring. In fact, contrary to the usual constructive design techniques, the choice of material is based on high friction of the components in the area of the friction ring that rotate relative to one another. At the same time, the material selected for the one-piece friction ring is not too brittle and sufficiently elastic to prevent the input side from jamming motionlessly with the cover and to obtain a high contact pressure over a sufficiently large spring deflection with a flat spring characteristic of the friction ring.

In particular, the friction ring is made of a plastic material. The plastic material can in particular be made of ABS, PEEK, PET, PPS, PA, resulting in a sufficiently wear-resistant friction ring which, with sufficient elasticity, can provide a high contact pressure over the spring deflection to be expected of the first partial area.

In particular, the first partial area bears against the entry side or the exit side or the cover, preferably on the entry side.

In particular, the first partial area forms a linear contact with the input side or the output side or the cover.

In particular, the friction ring has at least one dimensionally stable second partial area which forms a planar contact with the input side or the output side, preferably with the output side or with the cover.

In particular, it is provided that the first partial area bears linearly on the input side and the second partial area bears flat on the output side or the cover. The first portion can have a protruding elevation in the manner of a sealing lip, which limits the line contact between the first ten sub-area and the input side or the output side.

The friction ring is in particular ring-shaped and runs around in a circumferential direction.

In particular, the friction ring is connected to the cover (or connected to the cover in a rotationally fixed manner relative to the circumferential direction), the friction ring being rotatable together with the cover and (possibly additionally) the output side relative to the input side along the circumferential direction.

In particular, the friction ring is designed so that if there is too much axial displacement of the output side or the pulley, e.g. B. due to axial vibrations, which leads to excessive compression of the friction ring, to be pressed so far in the manner of a plate spring that a further area of the friction ring comes to rest on the input side, whereby a stronger counterforce from the friction ring to the axially shifted Output side can be impressed and further axial displacement is prevented or at least made more difficult. The stiffness and thus the spring characteristic and the frictional effect can be suitably adjusted via the design of the cross section and the shape of the friction ring, which is designed in particular in the manner of a sealing lip, and/or the design of the connection or the transition of the first partial area and the second partial area.

In particular, the friction ring is made from at least two different plastic materials. The plastic materials are selected in particular with regard to the required special properties of the first subarea and the second subarea. In particular, the friction ring can be produced by a multi-component injection molding process (eg two-component injection molding process).

In particular, at least the first partial area is designed in the manner of a disc spring (however made of a plastic material). As a result, the friction ring can impress a high axial contact pressure with a small spring deflection. Due to the small extension in the axial direction compared to other spring elements, the friction ring designed as a plate spring can be integrated very easily into the installation space between the input side and the output side. In addition, the result is a three-dimensional design of the friction ring, which enables the one-piece friction ring to be produced by cost-effective plastic injection molding.

The first partial area can in particular be embodied as a hollow body with a circumferential cavity in the circumferential direction, or as a solid material.

In particular, the at least one spring element is arranged in a volume formed at least by the output side and the cover, the volume being at least partially filled with a fluid (lubricant) and being sealed on the second side by the cover and the friction ring from the surroundings of the pulley decoupler .

The at least one spring element is supported with a spring force acting in the circumferential direction on a first stop on the input side and on a second stop on the output side (e.g. the cover) and via a sliding cup and/or the cover on the belt section at least opposite the radial one direction.

In particular, the input side (also referred to as the shaft connection area, since the input side can be connected or is connected in a rotationally fixed manner to a shaft, e.g. to a crankshaft) against a spring force of the at least one spring element and in particular against a damping effect of at least one torsional vibration damping device, relative to the output side (also referred to as the belt connection area, since the output side can be connected or is connected in a rotationally fixed manner to a belt via the belt section) can be rotated at most by an angular range extending in the circumferential direction (e.g. at most 30 angular degrees). The twist is z. B. limited by stops (first stops, second stops).

Torsional vibrations can at least be reduced via the relative rotation from the input side to the output side, which takes place against the spring force and possibly the damping effect.

In particular, the cover forms the output side together with another component (e.g. the belt connection area or the belt pulley). The volume filled with a fluid (lubricant, eg grease), in which the at least one spring element is arranged, is sealed off from the surroundings of the belt pulley decoupler via the friction ring arranged on the cover. In addition to the sealing function of the volume, the friction ring also forms an axial spring and thus replaces z. B. the previously used metallic disk spring, via which the output side and input side along the axial direction were previously clamped together.

The pulley decoupler is particularly useful for connecting a pulley to a crankshaft of a prime mover, e.g. B. one Motor vehicle provided. This is to prevent the transmission of torsional vibrations, e.g. B. the prime mover on the belt driven by the pulley, at least reduced or prevented. However, the pulley decoupler can also form a two-mass flywheel.

The use of indefinite articles (“a”, “an”, “an” and “an”), particularly in the claims and the description reflecting them, should be understood as such and not as a numeral. Correspondingly introduced terms or components are to be understood in such a way that they are present at least once and in particular can also be present several times.

As a precaution, it should be noted that the numerals used here (“first”, “second”, ...) primarily (only) serve to distinguish between several similar objects, sizes or processes, i.e. in particular no dependency and/or sequence of these objects, sizes or make processes mandatory for each other. Should a dependency and/or order be necessary, this is explicitly stated here or it is obvious to the person skilled in the art when studying the specifically described embodiment. If a component can occur several times (“at least one”), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

• 1: eine erste Ausführungsvariante eines bekannten Riemenscheibenentkopplers in einer Seitenansicht im Schnitt;
• 2: eine zweite Ausführungsvariante eines bekannten Riemenscheibenentkopplers in einer Seitenansicht im Schnitt; und
• 3: einen Riemenscheibenentkoppler in einer Seitenansicht im Schnitt.

The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be pointed out that the invention should not be limited by the exemplary embodiments given. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description. In particular, it should be pointed out that the figures and in particular the proportions shown are only schematic. Show it:

• 1 1: a first embodiment variant of a known pulley decoupler in a sectional side view;
• 2 Fig. 1: a second variant embodiment of a known pulley decoupler in a sectional side view; and
• 3 : a pulley decoupler in a sectional side view.

1 Figure 1 shows a first variant embodiment of a known pulley decoupler 1 in a sectional side view. The pulley decoupler 1 comprises an input side 2 and an output side 3 and a common axis of rotation 4 extending along the axial direction 13 as well as at least one spring element 5 acting between the input side 2 and the output side 3, by which the input side 2 and the output side 3 move in the circumferential direction 6 are rotatable against each other. The output side 3 is rotatably mounted relative to the input side 2 via a (plain) bearing 7 arranged on the input side 2 . Starting from the (plain) bearing 7, the output side 3 extends outwards in a radial direction 9 on a first side 8 of the at least one spring element 5 to a belt section 10 (on which a belt can be arranged, which can be connected via the belt section 10 or can be driven via the pulley decoupler 1). Starting from the belt section 10 and along the radial direction 9 inwards, a cover 12 extends on a second side 11 opposite the first side 8. The cover 12 is connected via a friction ring 16 to a plate spring 21, through which the output side 3 and the input side 2 are arranged braced against one another in relation to the axial direction 13 . The disc spring 21 is clamped by two elements of the input side 2 (on the one hand by the second stop 15 or the cover 12 and on the other hand by the torsional vibration damper 23). Cover 12 and output side 3 together form the volume 19 in which the spring element 5 is arranged. The volume 19 is at least partially filled with a fluid 20 . On the first side 8 the volume 19 is sealed off by a further friction ring 16 which bridges a gap between the input side 2 and the output side 3 .

2 shows a second variant embodiment of a known pulley decoupler 1 in a sectional side view. To the remarks 1 is referred to.

In contrast to the first embodiment variant, two friction rings 16 are arranged on the second side 11 of the spring element 5 in the second embodiment variant. The plate spring 21 is arranged between the friction rings 16 . One friction ring 16 is arranged on cover 12 . The other friction ring 16 is arranged between the disk spring 21 and the torsional vibration damper 23 .

Both friction rings 16 (on the second side 11) form sealing surfaces with the cover 12 or the cup spring 21 on the one hand and the torsional vibration damper 23 on the other hand.

3 Fig. 1 shows a pulley decoupler 1 in a sectional side view. The pulley decoupler 1 comprises an input side 2 and an output side 3 and along the axial direction 13 extending, common axis of rotation 4 and at least one acting between the input side 2 and output side 3 spring element 5, against the spring action of the input side 2 and the output side 3 in the circumferential direction 6 are mutually rotatable. The output side 3 is rotatably mounted relative to the input side 2 via a (plain) bearing 7 arranged on the input side 2 . Starting from the (plain) bearing 7, the output side 3 extends outwards in a radial direction 9 on a first side 8 of the at least one spring element 5 to a belt section 10 (on which a belt can be arranged, which can be connected via the belt section 10 or can be driven via the pulley decoupler 1). Starting from the belt section 10 and along the radial direction 9 inwards, it extends on a second side 11 opposite the first side 8

Starting from the belt section 10 and along the radial direction 9 inwards on a second side 11 opposite the first side 8 in an axial direction 13 extending along the axis of rotation 4, a cover 12 extends. Between the cover 12 and the input side 2 is a friction ring 16 consisting exclusively of plastic material is arranged, which has a first partial area 17 which is elastically deformable and which generates a spring force acting in the axial direction 13 .

The friction ring 16 replaces the otherwise usual combination of friction ring(s) and metal plate spring 21, so that the number of parts can be reduced by the friction ring 16 and assembly can be simplified.

The friction ring 16 is designed in one piece. The friction ring 16 is ring-shaped and runs around in a circumferential direction 6 . In addition to the first partial area 17 , the friction ring 16 has a dimensionally stable second partial area 18 which forms a planar contact with the output side 3 or with the cover 12 . The first partial area 17 rests on the input side 2 . The first partial area 17 forms a linear contact with the input side 2 . The first partial area 17 has a protruding elevation 24 in the manner of a sealing lip, which provides the line contact between the first partial area 17 and the input side 2 . The first partial area 17 is designed as a solid material.

The friction ring 16 is connected to the cover 12 (possibly connected to the cover 12 in a rotationally fixed manner relative to the circumferential direction 6), the friction ring 16 together with the cover 12 and (possibly additionally) the output side 3 relative to the input side 2 along the circumferential direction 6 is rotatable.

The first partial area 17 is designed in the manner of a disc spring 21 (although made of a plastic material). As a result, the friction ring 16 can apply a high axial contact pressure force along the axial direction 13 with a small spring deflection. Due to the small extension in the axial direction 13 compared to other spring elements, the friction ring 16 configured as a cup spring 21 in the first partial area 17 can be integrated very easily into the installation space between the input side 2 and the output side 3 .

The at least one spring element 5 is arranged in a volume 19 formed at least by the output side 3 and the cover 12, the volume 19 being at least partially filled with a fluid 20 (lubricant) and on the second side 11 by the cover 12 and the friction ring 16 is sealed from an environment 22 of the pulley decoupler 1.

The at least one spring element 5 is supported with a spring force acting in the circumferential direction 6 on a first stop 14 on the input side 2 and on a second stop 15 on the output side 3 (the cover 12) and via the cover 12 on the belt section 10 at least opposite the radial Direction 9 off.

The input side 2 is rotatably connected to a shaft such. B. can be connected to a crankshaft and against a spring force of the at least one spring element 5 and in particular against a damping effect of at least one torsional vibration damping device, relative to the output side 3 (also referred to as the belt connection area, since the output side 3 can be connected to a belt in a rotationally fixed manner via the belt section 10 or . Is connected) by a maximum in the circumferential direction 6 extending angular range (z. B. at most 30 degrees) rotatable. The torsion is limited by the stops 14,15.

Reference List

1

Pulley decoupler

2

entry page

3

exit page

4

axis of rotation

5

spring element

6

circumferential direction

7

warehouse

8th

first page

9

radial direction

10

strap section

11

second page

12

lid

13

axial direction

14

first stop

15

second stop

16

friction ring

17

first section

18

second section

19

volume

20

Fluid

21

disc spring

22

vicinity

23

torsional vibration damper

24

elevation

Claims (7)

Pulley decoupler (1) with an input side (2) and an output side (3) and a common axis of rotation (4) and at least one spring element (5) acting between the input side (2) and the output side (3), against the spring action of which the input side (2) and the output side (3) can be rotated relative to one another in a circumferential direction (6), the output side (3) being rotatably mounted relative to the input side (2) via a bearing (7) arranged on the input side (2), the output side ( 3) starting from the bearing (7) on a first side (8) of the at least one spring element (5) in a radial direction (9) outwards to a belt section (10), wherein starting from the belt section (10) and a cover (12) extends along the radial direction (9) inwards on a second side (11) opposite the first side (8) in an axial direction (13) extending along the axis of rotation (4), with between the cover l (12) and the input side (2) a friction ring (16) consisting exclusively of plastic material is arranged, which has at least a first partial area (17) which is elastically deformable and which generates a spring force acting in the axial direction (13). Pulley decoupler (1) after claim 1 , wherein the first portion (17) rests on the input side (2) or on the output side (3). Pulley decoupler (1) according to one of the preceding claims, in which the first portion (17) forms a line-shaped contact with the input side (2) or the output side (3). Pulley decoupler (1) according to one of the preceding claims, wherein the friction ring (16) has at least one dimensionally stable second partial area (18) which forms a planar contact with the input side (2) or the output side (3). Pulley decoupler (1) according to any one of the preceding claims 3 and 4 , wherein the friction ring (16) is made of at least two different plastic materials. Pulley decoupler (1) according to one of the preceding claims, wherein at least the first portion (17) is designed in the manner of a plate spring. Pulley decoupler (1) according to one of the preceding claims, wherein the at least one spring element (5) is arranged in a volume (19) formed at least by the output side (3) and the cover (12), the volume (19) being at least partially is filled with a fluid (20) and is sealed off on the second side (11) by the cover (12) and the friction ring (16) from an environment (22) of the pulley decoupler (1).

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